Prediction of friction in EHL contacts for drivetrain applications

Prediction of frictional losses in elastohydrodynamic lubricated contacts is of particular importance from the viewpoint of energy efficiency, thus reduced levels of emissions. There are increasingly stringent government regulations. Thus, the industry strives to identify potential losses and improve energy efficiency. Most losses occur in a large number of load bearing conjunctions in all forms of mechanisms and machines. These losses are affected by the operating conditions, such as applied load, contact kinematics and generated temperature. Prediction of prevailing conditions, such as generated pressures, film thickness is the prelude to evaluation of frictional power losses. Many contact conjunctions in vehicular drivetrains are subjected to elastohydrodynamic conditions, the fundamental aspects of which are still evolving. In particular, effective prediction of performance of elastohydrodynamic lubricated (EHL) contacts is subject to inclusion of realistic contact conditions, particularly with respect to inlet and outlet boundary conditions as well as kinematics of contact. This paper demonstrates the importance of boundary conditions on predictions of prevailing situations